floppycontrol(1) General Commands Manual floppycontrol(1)
floppycontrol - floppy driver configuration utility
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floppycontrol [-p] [--pollstate] [--printfdstate]
[-a operation-abort-threshold] [-c read-track-threshold]
[-r recalibrate-threshold] [-R reset-threshold]
[-e reporting-threshold] [-f] [-x] [-d drive][-F] [-T]
[-reset condition] [--debug] [--nodebug] [--messages]
[--nomessages] [--broken_dcl] [--working_dcl] [--inverted_dcl]
[--no_inverted_dcl] [--silent_dcl_clear] [--noisy_dcl_clear]
[-ccmos-type] [-hlt hlt] [-hut hut] [-srt srt] [-o spindown]
[-u spinup] [-s select-delay] [-rps rotations-per-second]
[-O spindown-offset] [-track max-tracks] [-timeout seconds]
[-C check-interval] [-n native-format]
[-autodetect autodetection-sequence] [-P] [--clrwerror]
The floppycontrol program is used to configure the floppy driver.
--help Print a help screen.
Selects the drive to configure. The default is drive 0
One time actions
The following floppycontrol options don't set a configuration parame-
ter, but perform a one-time action. They are available to anybody who
has write access to the drive
Flushes (throws away) the dirty data buffers associated with
Ejects the disk out of the drive (Sparc). The dirty buffers are
first committed to disk before ejecting it. Fails if the disk is
Resets the FDC under condition . Condition may be one of the
0 resets the FDC only if a reset is needed anyways,
1 resets the FDC also if a raw command has been performed
since the last reset, and
2 resets the FDC unconditionally.
This command may be needed after some failed raw commands (see
Issues an end format ioctl. This might be needed after exiting a
fdformat in an unclean way. superformat is not subject to this.
Printing current settings
--type Print out the drive name of a floppy device. This is used by the
MAKEFLOPPIES script. The drive name is a letter (describing the
drive type) followed by the capacity of the format in bytes. The
letter is E for 3.5 ED drives, H for 3.5 HD drives, D for 3.5 DD
drives, h for 5.25 HD drives and d for 5.25 DD drives. The drive
type letter corresponds to the oldest drive type supporting the
format of this device node (not necessarily the type of the
drive referred by this node.) For the generic format nodes
(/dev/fd0 et al.) the name of "native format" of the drive is
printed, and for the default formats, if a generic format has
been redefined, its name becomes (null).
Prints out the configuration of the drive. The names of the var-
ious fields are the same as the names of the option to set them,
Prints out the cached internal state of the driver. The first
line lists various attributes about the disk:
These are only updated when the drive is accessed.
is the time when the motor became switched on for the
is the time when the drive became selected for the last
is the time when the first read request after the last
spin up completed.
is the index of the autodetected format in the autodetec-
tion sequence for this drive.
is the cylinder where the drive head currently sits. If
this number is negative, it has the following meaning:
* -1 means that the driver doesn't know, but the
controller does (a seek command must be issued).
* -2 means that the controller doesn't know either,
but is sure that it not beyond the 80th track.
The drive needs a recalibration.
* -3 means that the head may be beyond the 80th
track. The drive needs two successive recalibra-
tions, because at each recalibration, the con-
troller only issues 80 move head commands per
is the highest block number that has been read.
is a boolean which is set when a sector that is not on
cylinder 0/head 0 has been read. These are used for
smart invalidation of the buffer cache on geometry
change. The buffer cache of the drive is only invali-
dated on geometry change when this change actually
implies that a block that has already been read changes
position. This optimization is useful for mtools which
changes the geometry after reading the boot sector.
is roughly the number of disk changes noticed since boot.
Disk changes are noticed if the disk is actually changed,
or if a flush command is issued and for both cases if any
I/O to/from the disk occurs. (i.e. if you insert several
disks, but don't do any I/O to them, the generation num-
ber stays the same.)
refs is number of open file descriptors for this drive. It is
always at least one, because floppycontrol's file
descriptor is counted too.
is format type (as derived from the minor device number)
which is currently being used.
is date (in jiffies) when the drive was last checked for
a disk change, and a disk was actually in the drive.
Polls the drive and then prints out the internal state of the
driver.(--Printstate only prints out the cached information
without actually polling the drive for a disk change.)
Prints out the state of the controller where the target drive is
spec2 are the current values of those registers.
rate is current data transfer rate
is true if a raw command has been executed since the last
reset. If this is the case, a reset will be triggered
when a drive on the same FDC is next opened.
dor is the value of the digital output register. The 4 high
bits are a bit mask describing which drives are spinning,
the 2 low bits describe the selected drive, bit 2 is used
to reset the FDC, and bit 3 describes whether this FDC
has hold of the interrupt and the DMA. If you have two
FDCs, bit 3 is only set on one of them.
is the version of the FDC. See
`linux/include/linux/fdreg.h' for a listing of the FDC
reset is true if a reset needs to be issued to the FDC before
processing the next request.
is true if this FDC needs configuration by the FD_CONFIG-
is set if the FDC understands the FD_CONFIGURE command.
describes the perpendicular mode of this FDC. 0 is non-
perpendicular mode, 2 is HD perpendicular mode, 3 is ED
perpendicular mode, and 1 is unknown.
is the address of the first I/O port of the FDC. Nor-
mally, this is 0x3f0 for the first FDC and 0x370 for the
Drive type configuration and autodetection
The following options handle the different available drive types, such
as double density vs. high density vs. extra density drives, and 5 1/4
drives vs 3 1/2 drives. Usually the drive type is stored in a non-
volatile memory, called CMOS, under the form of an integer ranging from
1 to 6.
Different drive types are able to handle and autodetect different for-
mats (different autodetection lists). They also have different "native
format name". The native format is the "usual" format with the highest
capacity supported by the drive. (For example 720KB on a double density
3 1/2 drive, and 1.2MB on a high density 5 1/4 drive.)
These settings are only changeable by the super user.
Set the virtual CMOS type of the floppy drive. This is useful if
* the physical CMOS type is wrong (this may happen with
BIOSes which use a non-standard mapping),
* you have more than two drives (the physical CMOS may only
describe up to two drives).
* you have a BIOS that allows swapping drives A: and B: for
Right now, this CMOS parameter is not used by the kernel, except for
feeding it back to other applications (for instance superformat, flop-
pymeter or MAKEFLOPPIES). It is also possible to supply a virtual CMOS
type with the cmos boot option (see section Boottime configuration).
If possible, I recommend you use the boot option, rather than floppy-
control, because the boot option also sets any parameters derived from
the CMOS type, such as the autodetection list and the native format,
whereas floppycontrol does not.
Set the autodetection sequence (see section Autodetection) The
autodetection sequence is a comma-separated list of at most
eight format descriptors. Each format descriptor is a format
number optionally followed by the letter t. For drive 0, the
format number is the minor device number divided by 4. The
autodetection sequence is used by the driver to find out the
format of a newly inserted disk. The formats are tried one after
the other, and the first matching format is retained. To test
the format, the driver tries to read the first sector on the
first track on the first head when t is not given, or the whole
first track when t is given. Thus, autodetection cannot detect
the number of tracks. However, this information is contained in
the boot sector, which is now accessible. The boot sector can
then be used by mtools to configure the correct number of
means to try out the formats whose minor device numbers are 28
(1.44M), 16 (720KB), 96 (1.76MB), and 100 (1.92MB), in this
order. For the 1.76MB format, try to read the whole track at
Reading the whole track at once allows you to distinguish
between two formats which differ only in the number of sectors.
(The format with the most sectors must be tried first.) If you
use mtools, you do not need this feature, as mtools can figure
out the number of sectors without any help from the floppy
driver, by looking at the boot sector.
Reading the whole track at once may also speed up the first read
by 200 milliseconds. However, if, on the other hand, you try to
read a disk which has less sectors than the format, you lose
I suggest that you put the most often used format in the first
place (barring other constraints), as each format that is tried
out takes 400 milliseconds.
Set the native format of this drive. The native format of a
drive is the highest standard format available for this drive.
(Example: For a 5 1/4 HD drive it is the usual 1200K format.)
This is format is used to make up the format name for the
generic device (which is the name of the native format). This
drive name is read back from the kernel by the MAKEFLOPPIES
script which uses it to decide which device nodes to create.
Configuration of the disk change line
Assumes that the disk change line of the drive is broken. If
this is set, disk changes are assumed to happen whenever the
device node is first opened. The physical disk change line is
This option should be used if disk changes are either not
detected at all, or if disk changes are detected when the disk
was actually not changed. If this option fixes the problem, I'd
recommend that you try to trace the root cause of the problem.
Indeed, this options results in reduced performance due to spu-
rious cache flushes.
The following hardware problems may lead to a bad disk change
* If the floppy cable is not inserted straight, or if it is
kinked, the disk change line is likely to suffer, as it
is on the edge of the cable. Gently press on both con-
nectors of the cable (drive and controller) to insure
that all wires make contact. Visually inspect the cable,
and if it shows obvious traces of damage, get a new one.
* On some drives, the locations disk change line may be
chosen by jumper. Make sure that your floppy controller
and your drive agree on which line is the disk change
* Some older drives (mostly double density 5 1/4 drives)
don't have a disk change line. In this case, you have no
choice other than to leave the broken_dcl option on.
Assumes that the disk change line works all right. Switching
from broken to working may lead to unexpected results after the
first disk change.
Assumes that this disk drive uses an inverted disk change line.
Apparently this is the case for IBM thinkpads.
Assumes that this drive follows the standard convention for the
disk change line.
Switches off silent disk change line clearing for this drive.
This section describes how to configure drive timings. To set these
parameters, you need superuser privileges. All times are in "jiffy"
units (10 milliseconds), unless otherwise specified.
Set the head load time (in microseconds) for this floppy drive.
The head load time describes how long the floppy controller
waits after seeking or changing heads before allowing access to
Set the head unload time (in microseconds) for this floppy
drive. The head unload time describes how long the floppy con-
troller waits after an access before directing its attention to
the other head, or before seeking.
Set the step rate (in microseconds) for this floppy drive. The
step rate describes how long the drive head stays on one cylin-
der when seeking. Setting this value to low (too fast seeks)
may make seeks fail, because the motor doesn't follow fast
Set the spinup time of the floppy drive. In order to do read or
write to the floppy disk, it must spin. It takes a certain time
for the motor to reach enough speed to read or write. This
parameter describes this time. The floppy driver doesn't try to
access the drive before the spinup time has elapsed. With modern
controllers, you may set this time to zero, as the controller
itself enforces the right delay.
Set the spindown time of this floppy drive. The motor is not
stopped immediately after the operation completes, because there
might be more operations following. The spindown time is the
time the driver waits before switching off the motor.
Set the spindown offset of this floppy drive. This parameter is
used to set the position in which the disk stops. This is useful
to minimize the next access time. (If the first sector is just
near the head at the very moment at which the disk has reached
enough speed, you win 200 milliseconds against the most unfavor-
This is done by clocking the time where the first I/O request
completes, and using this time to calculate the current position
of the disk.
Set the select delay of this floppy drive. This is the delay
that the driver waits after selecting the drive and issuing the
first command to it. For modern controllers/drives, you may set
this to zero.
Set the maximal disk change check interval. The disk change
line is checked whenever a read or write to the device is
issued, and it has not been checked for more than interval
This subsection describes how to switch the available debugging mes-
sages on and off.
Switch debugging output on. The debugging information includes
timing information. This option might be useful to fine-tune the
timing options for your local setups. (But for most normal pur-
poses, the default values are good enough.)
Switch debugging output off.
Print informational messages after autodetection, geometry
parameter clearing and dma over/underruns.
Don't print informational messages after these events.
Error Handling Options
The following options configure the behavior of the floppy driver in
case of read/write errors. They may be used by any user who has write
privileges for the drive. Whenever the floppy driver encounters an
error, a retry counter is incremented. If the value of this counter
gets bigger than the thresholds described below, the corresponding
actions are performed at the next retry. The counter is reset when the
read or write finally terminates, whether successfully or not.
Tell the floppy driver to stop trying to read/write a sector
after operation-abort-threshold retries, and signal the I/O
error to the user.
Tell the floppy driver to switch from track-reading mode to sec-
tor-at-a-time-mode after read-track-threshold retries.
Tell the floppy driver to recalibrate the drive after recali-
Tell the floppy driver to reset the controller after reset-
threshold retries. After a controller reset, the floppy driver
also recalibrates all drives connected to that controller.
Tell the floppy driver to start printing error messages to the
console after error-report-threshold retries.
Write error reporting
Due to the buffer cache, write errors cannot always be reported to the
writing user program as soon as the write system call returns. Indeed,
the actual writing may take place much later. If a write error is
encountered, the floppy driver stores information about it in its per
drive write error structure. This write error structure stays until
explicitly cleared. It can for example be queried by a backup program
which wants to make sure that the data has been written successfully.
Clears the write error structure.
Prints the contents of the write error structure:
is a count of how many write errors have occurred since
the structure was last cleared.
is the maximal number of retries that were needed to com-
plete an operation (reads, writes and formats).
is where the first (chronologically) write error
is the disk change generation in which did the first
write error occurred. The disk change generation is a
number which is incremented at each disk change.
Other drive configuration options
This subsection lists per drive configuration options, which don't fit
in any other category. They are available only to the superuser:
Set the maximal numbers of physical tracks that this drive may
handle. If you have a drive which is only able to handle 80
tracks (making strange noises when you try to format or read a
disk with more than 80 tracks), use this option to prevent
unprivileged users of damaging your drive by repeatedly reading
disks with more than 80 tracks.
If you trust your users and your disks, you don't need this.
With most drives you don't need to worry anyways. See section
More cylinders, for details.
Set the number of sectors beyond which sector interleaving will
be used. This option will only be used by the FDFMTTRK ioctl.
The fdformat command, which is now considered obsolete, uses
FDFMTTRK ioctl, but superformat does not.
Fdutils' texinfo doc
fdutils-5.5 03Mar05 floppycontrol(1)
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